What makes a plane(gider) fly slow, steady and not sink? (much..) - RC Groups
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Mar 15, 2009, 09:21 PM
Physics hate's my ideas
GreenAce92's Avatar

What makes a plane(gider) fly slow, steady and not sink? (much..)

So... heres my situation

I am nowhere near any nice sloping sites... i am near a lake(lake erie) but i dont have any sloping sites like i said, maybe somewhere i've seen a few small ones but i am 20miles away from there.

So my goal is to make a Smooth Flat Land thermalling DLG Flying Wing(thats right because my material doesnt let me build strong reg style birds) i have built 2 designs recently, the Swordfish is by far the best, but sinking rate sucks...

Last flight of the Swordfish (6 min 6 sec)

ill have a video of the Barracuda up in a bit. Pics at least, this was an unstable plane, so in order to keep my steering/pitch working fine, and keep Stability from transition of Vertical to horizontal flight(DLG) without a programmed trim(because i cant at the moment) i will keep the basic barracuda design but with the triangle towards the front, this 40in model launched very high!(for me anyways) i got up around 80ft or so, there were plenty of thermals, boomers in fact(seagulls were so high they were spots) but since the sink rate and instability i couldnt stay in, i did for a few tight circles but not much
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Mar 15, 2009, 11:58 PM
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I don't see anything wrong with that airplane. Considering aspect ratio (which yours is pretty not big) and launch height (which yours is looking just fine) I think your flight durations are pretty fair.

The trick now is flying smoooooth so you can read the air as your airplane flies through it.

Is your pitch trim working at all? For my 2-channel ship, I launch with one trim setting, then use a couple of clicks nose up for cruise. One or two more when thermalling. The other thing you can do is make the servo arms smaller, and the control arms longer - that makes the control throws less, and makes for smoother flight.

Try some of that, but above all, fly a LOT! Thermals are invisible to us humans - that's part of the challenge. The airplane is a device for seeing thermals, and it will show you, if you aren't fiddling with the controls. So, keep launching good, and now work on smoooooth flying.

Cripes a'mighty, Ace - you've come a long way.

Yours, Greg
Mar 16, 2009, 01:21 AM
Registered User
I think you'd find that a conventional configuration would hang up there longer. And I don't think the Supergee style is the only way to do it. You might sacrifice a little bit of performance, but I think with a moderately low aspect ratio and a boxy fuse, you could make an all wood glider with a tail that would hang up there better. Or maybe a foam wing and wood fuselage and tail. With a spar of some sort in the wing. Or you could break down and build a Gambler or something.

For a flying wing, yours looks pretty good. What kind of hang time are you getting? if you're getting 45 seconds or so, that's probably pretty good, since you're not launching as high as you would with a regular DLG. Looks like you're a strong thrower.
Mar 16, 2009, 01:22 AM
Registered User
P.S. If it's unstable, try moving the cg a bit forward.
Mar 16, 2009, 02:02 AM
Physics hate's my ideas
GreenAce92's Avatar
Well the see, actually i should be quite thankful for this which i am believe me. Because of my novish sodering skills(my soddering gun sucks) i unsodered a couple diodes off here and there trying to attach a random antennae somewhere because i unsodered the original sodder point for the rx wire. So... i killed 1 3.6gram reciever today 4ch and a far range 6ch hitec receiver, im not a happy kid. This is the happy part, because i do not have a job i almost was not able to fly for a while, i'm applying for a job, so i went through all of my broken receivers and out of the two micro hitec o5s's, 2 corona 4ch ligh rx's and 4channel ppm rx, i found one of the hitec micro o5s which had ch2 not working... so... i had to mix in 2 mixs both switched on by ch7 i had 1 servo on ch1 and then the other on ch4. So because im doing an elevon mixing i did 2 mixing

Mas: 1
Slv: 4

Mas: 2
Slv: 4

but i wasnt able to do the third function(i tried) where ch1 and ch2 are both raised/ lowered by throttle switch. But im happy anyways just means that im going to have to build a smooth transitioning ship. The launch heights i got today were amazing! 80+ feet at times i would say and i was catching lots of thermals, only problem was when i would turn(downwind) my wing would dip and gain speed quick, thus falling out.

Anyways im going to work on a small 30in span bird, im calling it sunfish for that weird big fish thats called a sunfish but mainly its for the pancake shape i have a pic below of what im goin to try. Im going for thicker airfoil, see now that i have launch height, i need gliding

from an 80ft throw and only a 30+ second glide that sucks! i havent even reached 1min of gliding time yet... so i've got quite a bit to do still as you can see... although i may go for a higher aspect ratio but i dont know something about this designs tells me it' work well, plus the control surfaces are farthest back, unlike my Barracuda where there was a wing surface behind my elevons, really screwed me up, my plane wanted to fly upside down alot(neutral CG)

and whats even weirder is that when i would turn, the elevons would act as brakes, but too much as i would do this insane wing drop lol, plane would not turn but stall one wing and do like a side slip really bad...

i was almost desperate enough(thought my only rx left only had 1 control) to build a glider that somehow was able to be controlled by pitch/roll by only 1 control surface, taps would be pitch and longer throw would be turning, like an ellipse wing kinda bird thankfully i have a working radio system lol
Last edited by GreenAce92; Mar 16, 2009 at 02:09 AM.
Mar 16, 2009, 02:12 AM
Physics hate's my ideas
GreenAce92's Avatar
Just so you guys know
I numbered my planes
Ace 1 (Swordfish)
Ace 2 (barracuda)
Ace 3 unnamed
Ace 4 (Sunfish)---workin on this tomorrow

video of Barracuda:
Barracuda (4 min 4 sec)

the barracuda and the Swordfish both had relatively thin airfoil in order to penetrate the air better, so that may have made me glide less. Also i used to do sharp edges, now im doing rounded edges kinda like as if it were routed.

or maybe i will combine Ace 3 and 4 i'll make a blended body effect so i can have both a long Root Chord(more stability for discus throw) and high aspect ratio on outer tips, plus the elevons will be on the farthest back aerodynamic forces speaking...
Mar 16, 2009, 02:18 AM
Physics hate's my ideas
GreenAce92's Avatar
ahhh my camera makes me so angry those spots... the main one is the biggest blotch the rest i think i can wipe off
Its crazy you can "hear" drag lol its like when i throw it, it makes this ugly sound, and it slows down dramatticaly yeah i def am a thrower, as i can climb a tree without branches 30ft straight up with just body strength and arms, plus i swim its just a clean airfoil, longer span and better tail plus a well balanced plane.
Mar 16, 2009, 02:31 AM
Physics hate's my ideas
GreenAce92's Avatar
This is more like it, a blended body, high aspect on outer tips, and low on inside gives long root chord too
Mar 16, 2009, 03:10 AM
Registered User
prodjx's Avatar
Your doing real well with what you have. This morning from a discus launch of a friend's 60" bashed dlg I managed to get to speck out altitude, 600'+ feet and was up for about 20 min's. possibly my longest dlg flight, then in the afternoon it was off to "A" mountain for some sloping, BTW there's an "A" mountain thread on the slope forum here on rcgroups, 44,000+ view's and 85+ page's of photo's and comentary you might like it. Dave

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